Abstract
This paper considers the problem of estimating traffic performance characteristics at traffic roundabouts. One and two lane roundabouts are considered with the results consisting of analytical expressions for capacity, queue length, and delay. Where drivers have a choice of lane for a manoeuvre, a user optimal model is used to allocate flow to alternative lanes. The analysis is suitable for inclusion in traffic assignment models which explicitly represent traffic conflicts at intersections, or in stand-alone analytically based computer programs which analyse a single roundabout.(A).